A while back (5 years?), I read that the typical Tower Records outlet in the US would carry about 60,000 individual titles. A typical mass marketer such as Walmart carried maybe 5000. Now, Tower's brick-and-mortar stores are gone in America. (I stumbled upon one in Tokyo 2 years ago.) The smaller indies are closing, and the mass marketers such as Walmart and Best Buy are the only game in town for much of the US as far as actual "stores."
Here in Austin we still have a few viable indie outlets, though several others have closed.
As a teen in NYC, I used to buy records from my job earnings if I liked the cover and the packaging notes. Made some great discoveries that way. That's still possible online, but it sure is an adaptation.